There are several well known qualitative laboratory procedures for identifying drugs of abuse. These include Thin-Layered Chromatography (TLC), the Enzyme Multiplied Immuno-chemical Test (EMIT), Radioimmunoassay (RIA) and Gas-Liquid Chromatography (GLC). Each of these well known procedures require skilled technicians and relatively sophisticated equipment. Consequently, the testing procedure is necessarily expensive.
With the ever increasing rise in the use of abuse-type drugs, the need for detecting and identifying those drugs and their metabolites is becoming more important. With this need, many more tests are required to monitor the use of abuse-type drugs.
Thin layer chromatography screening procedures for detecting drugs in urine require the careful preparation of a test specimen and then a skillful application of that test specimen to a plate placed into a developing chamber. Once the plate is removed from the chamber and dried, it is sprayed with visualization reagents. Location and color of spots are compared with those of known standards. Qualitative judgments are made as to the presence of various drugs in the unknown sample. The procedure is tedious, time consuming and requires skilled personnel to interpret the results.
The EMIT procedure is a semi-quantitative immunoassay for drugs of abuse in biological fluids. The laboratory test requires trained technicians to perform and the equipment necessarily costs several thousands of dollars. The RIA procedure is a sensitive and quantitative laboratory procedure for detecting drugs of abuse. The various immunochemicals are labeled with radioactive compounds and require special care in their use and disposal. A license is required from the government to use this laboratory procedure because of the presence of radioactive materials. The GLC procedure can provide the highest degree of accuracy in drug analysis. However, the necessary equipment is expensive and the procedure is complicated. Consequently, highly trained personnel are required for its use.
The visualization reagents used in thin-layer chromatography are well known and their use is explained in U.S. Pat. No. 3,590,006. A particular method of handling the chemical visualization reagents for the TLC procedure is found in the U.S. Pat. No. 3,912,655. Here dry strips of paper impregnated with fixed amounts of the visualization reagent are prepared as a storage medium for the reagent to be used in the thin-layer chromatography procedures. Both of these disclosures are directed to producing a drug abuse test paper designed to replace the thin-layer chromatography procedure. Thus, both are designed to produce both a qualitative and quantitative analysis of abuse-type drugs in a biological fluid.
The U.S. Pat. No. 3,955,926 discloses a test process suitable for identifying narcotics in solid form. A sample of the material which is suspected to be a narcotic is subjected to a solvent for that particular narcotic. An absorbent, impregnated paper containing at least one component of a color reagent in dry form is then subjected to the solvent. This particular prior art test is not applicable to the detection of the presence of an abuse-type drug in a biological fluid such as urine.
A drug abuse test indicator device and a method of making same is disclosed in the international publication WO No. 84/02397. Here the matrix of a bibulous material is impregnated with a dry staining agent in precise amounts which are prepared in accordance with unique procedures whereby pH insensitivity and unique color change sensitivities to test fluids are obtained. This disclosure is said to be an improvement over the procedure disclosed in U.S. Pat. No. 3,915,639 which discloses the use of coatings on a carrier body requiring the use of an ion exchange resin, a staining agent and a color intensifier-stabilizer material. Each of these earlier disclosures make use of the visualization reagents commonly used in the thin-layer chromatography procedures. Both of these disclosures are directed to producing a drug abuse test paper designed to replace the thin-layer chromatography procedure. Thus, both are designed to produce both a qualitative and quantitative analysis of abuse-type drugs in a biological fluid.
Major difficulties exist in the production of the drug abuse test papers designed to replace the thin-layer chromatography procedure. These difficulties are associated with the necessity to use extremely controlled environments in the production of the papers. Thus, large production requirements for such papers while achieving commercial consistency has been a major problem. However, these papers represent the first successful attempts to detect the presence of abuse-type drugs by having visualization reagents present in a carrier matrix material change color within that matrix upon the direct application of a test specimen.
In view of the difficulties associated with known procedures and drug abuse test papers, the diagnostic test paper of the present invention has been developed for use as a confirmatory test for the presence of abuse drugs. The present system developed in accordance with this invention is not intended for monitoring therapeutic levels nor as a basis for any therapeutic treatment based on test results. The invention of this disclosure is designed as a simplified screening method providing rapid qualitative results for use in determining the need for additional or confirmatory testing. The basic idea is to screen the numerous samples of biological fluids collected at collection centers for drugs of abuse and their screening programs and determine which ones are a positive. Only those which show a positive result are then sent on the laboratory for further testing.
The diagnostic test procedure and its equipment is readily understood by persons who are unskilled in chemical laboratory procedures. That is, the primary users of the test will be the staff of the various collection centers such as clinics specifically set up for screening programs, methadone treatment centers and the like.
The procedure of the present invention is a qualitative test based on color producing visualization reagents used in thin-layer and paper chromatography. In general, TLC visualization reagents are used to react with materials of interest to produce an area that is visually distinct from the background due to unreacted reagent. The invention of this system does not attempt the separation and identification of individual components. Rather, the system is a method of screening biological fluids to determine the aggregate presence of materials which react with the visualization reagent impregnated in the test paper. Through the use of unskilled personnel, very inexpensive equipment and the rapid determination of negative results, the screening procedure of the present invention provides an extremely important advance in the drug abuse detection technology. That is, thousands of tests will no longer have to be conducted using the more sophisticated TLC, EMIT, RIA and GLC procedures.